Art of treating ores.



Ores, of which the iollowingds a'-'s'pec ification.

nofsnar iisnnrenr, orrl'rrsnnne PENNSYLVANIA.

Specification of Letters Patent.

am or 'r'nns'nms onns.

Patented July 2, 1907.

x Application filed August 28,1906. Serial Ho. $32,402

To all wlioni it mayvconcerril Be it lmown that I, Ro'snnr McKNmn'r, a-citizen of the UnitedStates, residing at; l?ittsburg, in the county "of Allegheny'and-State of Pennsylvania; have invented new and useful Improvements jn lthe of Treating My invention reference to "treatmen" of ores by a chloridizing- I effect the roasting by means of a superheated oxygen containing .gas. having a temperature of abQut' 5009 Ci'when entering the furnace, preferably withiiut any outside source of.

heat, 1 project upon the ore while it is being roasted and agitated a superheated oxygen containing gas having a temperature .of about 5oo9 p.' 'r1s s greatly hastensand the necessary reactionsg (whichse pp r s ys i lm by h h t b u y he p r at do rs i t n se i liyjthie as; t is the is not cooled by-th may duction of cold air, and'by the heat'caused by the in-'";

rapid-ity' of the reactions produced,-"renders a less degreeofheat the or obviates entirely the need for Employment: of exterior heat, -I'It 8139,1115: makes thereaction much. thorough; and renders the velar tile product's or nearly so from gases that interfere I ing of ores, the reactions produced in any invented art with the successful operation of the process; I I now insdetaillthe manner in I practice-my invented.

The pres suitable- =for my.v invented method are ores containing materials such as sulfur,

silica, arsenic or'ariy other of the well known that render the ore intractable 'whenitreated'jyxan amalgamationproces; but which rendered in nocuous by combining them with oxygen. These'ores include those 'where, for any reason, some of the materials are introduced into the ore. "As an:

oxygen containing gas, I'usually employ steam or atmospheric air or a mixture of steam and I I make a mixture of the ore to be roasted with salt. ,The ore is reduced'to a fine consistency, most'advantageously, to about 30 mesh. The ore and salt mix'- ture should, of course be intimate. Practically salt to about 10 7& of the ore isadded. This percentage how- 'ever depends entirely upon the quantity of the mate rials to be converted into oxysodium salts.

The mixture is roasted with agitation. This roasting can be started either by the application of heat-other than that produced by the heated oxygen containing this roasting and agitatin g'a large and preferably continuous supply of superheated oiygen containing gas such as steam or airpreierably having atemperature of about 500 C. is directed upon the roast.

.j t The wasting is'donefpreiersbly in a revolving cylinder furnace, f0r,.by so doing, the agitation produced is thorough, the superheated oxygen containing gas- .such as air ore team or mixture of the two is kept near the surface of the ore, anew surface is continually pre sented to the s'ir and caking of the ore in the cylinder is prevented, Within reasonable limits the hotter the airor steam that is introduced the better. It can" be introduced intothe furnace if desired through the "ore withdrawal Preferably it is introduced as -a,

largejet or blast of air'or steam. The supplyoi oxygen, whether derivedfrom the air or steam supplies or helps to supplythe large amount of oxygen required I in the" conversion of the materials that render the crude or'e refractory arid increase .the temperature of the both'by its proper heat, and by the increased rapiditypi the reactionsproduced. Another advantage derived by the use of the superheated air or steam' consists in that the volatiliz'ed products-are free from reducing gases present in ordinary roasting, such as carbon monoxid; and thus renders it easier to' retain the volatiliz'ed metals in the form of soluble salts, I

Like all reactions produced in-the chloridizingroastare very complicated and, in their details, are un'cerunited with the ofthejsalt' to form'sodium' sulfate. This change is believed not to be immediate in The silica seems" to partly become silicatedirectly with the liberation of chlorin, and thus even the 4 gold becomes in part at least chloridized.

A typical probable resction'o'f an ore be cited and is shown below. This ore contains as materials rendering'the ore'r'efractory zinc sulfid, lead sulfid, iron pyrites and silica. r Y

- tain. The sulfids are decompoeed,-' and the sulfur Oi the-above equations, 1, 3 5, and 7 are and are therefore collected in a suitable condensing epparatus such aai's described in my Patent No. 737,103.

After the roast has been continued until the ore is rendered non-refractory, which will be when the elements that render itrefractory in its raw state are rendered innocuous through entering into compounds, chiefly oxysalts'oi sodium, the ore is removed from the furnace and preferably allowed to pass into a suitable amalgamator while it is still hot. ,A very suitable device for this purpose is the one invented by me and shown in my application for Letters Patent having the Serial Number 330887 filed Aug. 16, 1906; which enables also the resulting solution to be saved for further treatment by electrolysis or a. suitable chemical precipitant for the purpose of saving any metals which may have remained in solution; I

There may he of course cases in which the ores as taken from the-ground are not refractory but which are most easily treated by introducing elements that render them so and such ores are equallysusceptible to treatment by the above described method.

Having now described my invention wh'at'I claim and desire to secure Letters Patent is: y g

. 1. The art of reducing ores that contain elements rcn dering the same refractory, which consists inroasting a mixture of ground ore and suit by means 01' a super heated oxygen containing gas, the salt being in sufiicient quantity to furnish suiflcient sodium to substantially convcrt the elements rendering the ore reiractory, in its crude state into oxysalts of sodium, roasting and agitating the mixture of ore and gait, and simultaneouslf directing upon the same, a superheated 0151;} containing gas continuing the roast until the elements rendering the ore= refractory are thoroughly oxidized 'and metallic chlorids of metals contained in the ore are producedfcob looting and condensing these volatile chloride when vola tillzed. and treating the residue of the ore by amnlgama" tion, substantially as described.

2. The art of reducing ores that contain elements rendering the same refractory, which consists in roasting a mixture of ground ore and salt by means of a superheated oxygen containing gas having a temperature of about 500 C. on entering the furnace; the salt being in sufllclent quantity to furnish sufliclent sodlum'to substantially convert the elements rendering the orerefractory, in its crude state into oxysalts of sodium. roasting and agitating the mixture of ore and salt, and simultaneously directing upon the same, a superheated oxygen contain lug gas having a temperature ot about 500 (1., continuing the roast until the elements rendering the ore reiractory. are thoroughly oxidized, andmetullic chlorids of metal contained in the ore are produced, collecting and condensing these'volatlle chlorlds when volatilize-d. and

V treating the residue of the orc by amalgamation. sub stantially as described.

8. The art of reducing ores that contain elcmenlsrcm dering the same-refractory. which consists in roasting a mixture oi. ground ore and salt by means of a superheated oxygen containing gas without-any other source of heat. the salt being in suilicient quantity to furnish suificicnt sodium to substantially convert the elements rendering the ore refractory in its crude state into oxysalts of sodium, roasting and agitating the mixture of ore and salt. and simultaneously directing upon the same superlnawted o.. -gen containing gas such as air or steam. continuing the roast until the elements rendering (11% 019 refractoay urc boroughly oxidized. and metallic chiorids hfmmen ls i i i lf l0d in the ore are produced, collecting ahd coin liSl'lJg; these volatile chlorids when volutllizcd, and treating the residue of the ore by amalgamation. sub stantinlly as described.

A. The art of reducing ores that contain cle ients rcndcrlng, th e sz 1me refractory. which consists in roasting a mixture of ground ore and salt by means of a super lioatedtoxygen containing gas. the salt being in sufliclcnt quantity to furnish sufllcient sodium to substantially convert the element rendering the ore refractory, in its crude state into oirysnlts of sodium, roasting and agltat ing' the mixture of ore and salt, and simultaneously direnting upon the same. a superheated oxygen containing gas continuing the roast until the elements rendering the orc refractory are" thoroughly oxydized, and metallic chlorids of metals contained in the ore are .produced, collecting. and condensing these volatile chlorids when volutilized, and treating the residue of the ore by amalgamation and the resulting solution of the non-volatilized soluble ,chloridsv by a wet method llb5t3ntlilllf-j1 described. 7

The art of reducing ores that contain elements rendcring them refractory to treatment by amalgamation. which consists in roasting a mixture of finely divided ore and salt with agitation in a closed chamber and simultaneously, directing upon the said roasting ore, while thus incloscd and agitated, a superheated oxygen containing gas, continuing the roastnntil the elements rendering the ore refractory are oxidized, forming metallic chlorlds. and treating the ore residue by amalgamation substantially as described.

6. The art of reducing ores containing elements rendering the ore refractory in its'raw state, which consists in-- roasting the ore with suflicicnt salt to provide sulficient sodium to form oxys'odium salts of the elements rendering the ore refractory until the elements rendering the ore refractory are [or-med into innocuous compounds. and then subject the ore while hot from the roasting. to an amalgamat on process: substantially as described.

In testimony whereof I atlix my signature in presence of two witnesses.

ROBERT McKNlGH'l.

Witnesses: I

ELIAS Eerovn, Bru vruien FITZGERALD.

Iii-5 

